Supplemental Information (Other Noncurrent Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Disclosure Text Block Supplement [Abstract]
Asset retirement obligations	$ 322.9	$ 285.1
Pension benefits	236.1	192.3
Postretirement benefits	8.9	10.3
Derivative instruments	56.0	112.7
Long-term accrued income taxes related to U.S. tax reform	60.8	109.4
Contingencies related to uncertain tax positions	98.5	89.6
Contract liabilities	290.0	136.9
Environmental liabilities	67.2	50.2
Other	210.1	131.5
Other noncurrent liabilities	$ 1,350.5	$ 1,118.0

Carrying value of the obligation (known or estimated) arising from requirements to perform activities to remediate one or more sites, payable after twelve months or beyond the next operating cycle if longer.

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Amount of tax liability from transition tax on accumulated earnings of controlled foreign corporation deemed repatriated pursuant to Tax Cuts and Jobs Act, classified as noncurrent.

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